Acquired Immunodeficiency Disease (AIDS) presents a significant threat to the health of many in this country. Prevention of further Human Immunodeficiency Virus (HIV) transmission is dependent, in large part, upon the behavioral changes enacted by individuals. Although recent research findings suggest that behavior change is occurring, particularly among White gay men who are at higher risk for HIV infection, less is known about changes in other higher risk populations or about the psychological determinants of successful long term behavior change. The proposed SDA will support a program of research aimed at explicating possible psychological and interpersonal determinants of AIDS-related risk and risk reduction behaviors among two populations: sexually active, ethnically diverse, heterosexual young adults and gay and bisexual Black men. Theoretical models of attitude-behavior relationships of behavior change may assist in the development of AIDS prevention interventions. This SDA capitalizes on both current research already underway and the rich training resources at UCLA. The award would also facilitate candidate development in the areas of model-testing multivariate statistical techniques and survey methodology, both of which will assume increasing importance as social scientists seek to test predictive models of AIDS-related preventive behavior change.